stabilized retinal image

stabilized retinal image 

Image formed on the retina when neutralizing the fixation movements of the eye. The effect of these movements is thus eliminated and the image usually disappears after a few seconds. The methods used for stabilizing a retinal image are: (1) The target is placed at the end of a tube mounted on a tightly fitted contact lens. The whole device moves with every movement of the eyeball and the retinal image remains on the same retinal spot. (2) The subject is also fitted with a tight contact lens on the side of which is attached a small mirror. A test projected on the mirror is reflected onto a screen. The subject views the test through a compensating system of four mirrors and therefore as the eye moves the retinal image moves along with it and stimulates the same retinal spot. (3) Presentation of a target for a length of time smaller than the time necessary for the eye to perform a small eye movement. Presentations of less than 0.01 s usually fulfill this requirement. See fixation movements; Troxler's phenomenon.